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MBio Jun 2024Autophagy is an important biological process in host defense against viral infection. However, many viruses have evolved various strategies to disrupt the host antiviral...
UNLABELLED
Autophagy is an important biological process in host defense against viral infection. However, many viruses have evolved various strategies to disrupt the host antiviral system. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus with a large economic impact on the swine industry. At present, studies on the escape mechanism of PRRSV in the autophagy process, especially through chaperone-mediated autophagy (CMA), are limited. This study confirmed that PRRSV glycoprotein 5 (GP5) could disrupt the formation of the GFAP-LAMP2A complex by inhibiting the MTORC2/PHLPP1/GFAP pathway, promoting the dissociation of the pGFAP-EF1α complex, and blocking the K63-linked polyubiquitination of LAMP2A to inhibit the activity of CMA. Further research demonstrated that CMA plays an anti-PRRSV role by antagonizing nonstructural protein 11 (NSP11)-mediated inhibition of type I interferon (IFN-I) signaling. Taken together, these results indicate that PRRSV GP5 inhibits the antiviral effect of CMA by targeting LAMP2A. This research provides new insight into the escape mechanism of immunosuppressive viruses in CMA.
IMPORTANCE
Viruses have evolved sophisticated mechanisms to manipulate autophagy to evade degradation and immune responses. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus that causes enormous economic losses in the swine industry. However, the mechanism by which PRRSV manipulates autophagy to defend against host antiviral effects remains unclear. In this study, we found that PRRSV GP5 interacts with LAMP2A and disrupts the formation of the GFAP-LAMP2A complex, thus inhibiting the activity of CMA and subsequently enhancing the inhibitory effect of the NSP11-mediated IFN-I signaling pathway, ultimately facilitating PRRSV replication. Our study revealed a novel mechanism by which PRRSV escapes host antiviral effects through CMA, providing a potential host target, LAMP2A, for developing antiviral drugs and contributing to understanding the escape mechanism of immunosuppressive viruses.
PubMed: 38940560
DOI: 10.1128/mbio.00532-24 -
Journal of Virology Jun 2024Viruses have evolved a range of strategies to utilize or manipulate the host's cellular translational machinery for efficient infection, although the mechanisms by which...
UNLABELLED
Viruses have evolved a range of strategies to utilize or manipulate the host's cellular translational machinery for efficient infection, although the mechanisms by which infectious bronchitis virus (IBV) manipulates the host translation machinery remain unclear. In this study, we firstly demonstrate that IBV infection causes host shutoff, although viral protein synthesis is not affected. We then screened 23 viral proteins, and identified that more than one viral protein is responsible for IBV-induced host shutoff, the inhibitory effects of proteins Nsp15 were particularly pronounced. Ribosome profiling was used to draw the landscape of viral mRNA and cellular genes expression model, and the results showed that IBV mRNAs gradually dominated the cellular mRNA pool, the translation efficiency of the viral mRNAs was lower than the median efficiency (about 1) of cellular mRNAs. In the analysis of viral transcription and translation, higher densities of RNA sequencing (RNA-seq) and ribosome profiling (Ribo-seq) reads were observed for structural proteins and 5' untranslated regions, which conformed to the typical transcriptional characteristics of nested viruses. Translational halt events and the number of host genes increased significantly after viral infection. The translationally paused genes were enriched in translation, unfolded-protein-related response, and activation of immune response pathways. Immune- and inflammation-related mRNAs were inefficiently translated in infected cells, and IBV infection delayed the production of IFN-β and IFN-λ. Our results describe the translational landscape of IBV-infected cells and demonstrate new strategies by which IBV induces host gene shutoff to promote its replication.
IMPORTANCE
Infectious bronchitis virus (IBV) is a γ-coronavirus that causes huge economic losses to the poultry industry. Understanding how the virus manipulates cellular biological processes to facilitate its replication is critical for controlling viral infections. Here, we used Ribo-seq to determine how IBV infection remodels the host's biological processes and identified multiple viral proteins involved in host gene shutoff. Immune- and inflammation-related mRNAs were inefficiently translated, the translation halt of unfolded proteins and immune activation-related genes increased significantly, benefitting IBV replication. These data provide new insights into how IBV modulates its host's antiviral responses.
PubMed: 38940559
DOI: 10.1128/jvi.00830-24 -
Microbiology Spectrum Jun 2024We used phage display, antibody engineering, and high-throughput assays to identify antibody-accessible targets of . We report the discovery of monoclonal antibodies...
We used phage display, antibody engineering, and high-throughput assays to identify antibody-accessible targets of . We report the discovery of monoclonal antibodies (mAbs) binding to type 3 fimbrial proteins, including MrkA. We found that anti-MrkA mAbs were cross-reactive to a diverse panel of clinical isolates, representing different O-serotypes. mAbs binding to MrkA have previously been described and have been shown to provide prophylactic protection, although only modest protection when dosed therapeutically in a murine lung infection model. Here, we used a combination of binding and opsonophagocytic killing studies using a high-content imaging platform to provide a possible explanation for the modest therapeutic efficacy reported in that model. Our work shows that expression of type 3 fimbriae in culture is not homogenous within a bacterial population. Instead, sub-populations of bacteria that do, and do not, express type 3 fimbriae exist. In a high-content opsonophagocytic killing assay, we showed that MrkA-targeting antibodies initially promote killing by macrophages; however, over time, this effect is diminished. We hypothesize the reason for this is that bacteria not expressing MrkA can evade opsonophagocytosis. Our data support the fact that MrkA is a conserved, immunodominant protein that is antibody accessible on the surface of and suggest that additional studies should evaluate the potential of using anti-MrkA antibodies in different stages of infection (different sites in the body) as well as against biofilms in the body during infection and associated with medical devices.IMPORTANCEThere is an unmet, urgent need for the development of novel antimicrobial therapies for the treatment of infections. We describe the use of phage display, antibody engineering, and high-throughput assays to identify antibody-accessible targets of . We discovered monoclonal antibodies (mAbs) binding to the type 3 fimbrial protein MrkA. The anti-MrkA mAbs were found to be highly cross-reactive, binding to all strains tested from a diverse panel of clinical isolates, and were active in an opsonophagocytic killing assay at pM concentrations. MrkA is important for biofilm formation; thus, our data support further exploration of the use of anti-MrkA antibodies for preventing and/or controlling in biofilms and during infection.
PubMed: 38940542
DOI: 10.1128/spectrum.00400-24 -
Veterinary Surgery : VS Jun 2024To determine the feasibility of open cholangioscopy using disposable flexible endoscopes in canine cadavers and describe the surgical approach.
OBJECTIVE
To determine the feasibility of open cholangioscopy using disposable flexible endoscopes in canine cadavers and describe the surgical approach.
STUDY DESIGN
Ex vivo experimental cadaveric study.
SAMPLE POPULATION
Eight canine cadavers.
METHODS
Cadavers ranging from 5.8 to 43.8 kg underwent open transcholecystic cholangioscopy using a disposable flexible endoscope with a 3.8 mm outer diameter and 1.2 mm working channel and the surgical approach was described. The most distal anatomical region of the biliary tree towards the duodenal papilla that was visualized with the endoscope was recorded in each cadaver. A 2.7 mm rigid endoscope and a 1.9 mm flexible endoscope were also trialed and findings recorded. Endoscopic tools were trialed and their usage recorded.
RESULTS
The disposable flexible endoscope was feasible for visualization of the junction of the common bile duct, cystic duct, and hepatic ducts in all eight dogs. Cholangioscopy using a 2.7 mm rigid endoscope did not provide further distal visualization. The 1.9 mm flexible endoscope was able to traverse down to the level of the major duodenal papilla in a 43.8 kg cadaver. Use of certain endoscopic tools can be considered through the disposable flexible endoscope although fluid instillation was affected.
CONCLUSION
A 3.8 mm disposable flexible endoscope could be placed through an open transcholecystic approach to provide intraluminal endoscopic evaluation up to the level of the junction of the common bile duct, cystic duct, and hepatic ducts in dogs without cholecystic disease.
CLINICAL SIGNIFICANCE
Open transcholecystic cholangioscopy with a disposable flexible endoscope could provide a low-cost diagnostic and therapeutic tool in cases of obstructive biliary disease up to the level of the common bile duct.
PubMed: 38940529
DOI: 10.1111/vsu.14124 -
MSphere Jun 2024is an enteric pathogen that can cause a range of illnesses from mild diarrhea to pseudomembranous colitis and even death. This pathogen often takes advantage of...
UNLABELLED
is an enteric pathogen that can cause a range of illnesses from mild diarrhea to pseudomembranous colitis and even death. This pathogen often takes advantage of microbial dysbiosis provoked by antibiotic use. With the increasing incidence and severity of infections, coupled with high recurrence rates, there is an urgent need to identify innovative therapies that can preserve the healthy state of the gut microbiota. In this study, we screened a microbial metabolite library against . From a collection of 527 metabolites, we identified 18 compounds with no previously identified antimicrobial activity and metabolites that exhibited potent activity against growth. Of these 18 hits, five drugs and three metabolites displayed the most potent anti-. activity and were subsequently assessed against 20 clinical isolates of . These potent agents included ecteinascidin 770 (minimum inhibitory concentration against 50% of isolates [MIC] ≤0.06 µg/mL); 8-hydroxyquinoline derivatives, such as broxyquinoline and choloroquinaldol (MIC = 0.125 µg/mL); ionomycin calcium salt, carbadox, and robenidine hydrochloride (MIC = 1 µg/mL); and dronedarone and milbemycin oxime (MIC = 4 µg/mL). Unlike vancomycin and fidaxomicin, which are the standard-of-care anti-. antibiotics, most of these metabolites showed robust bactericidal activity within 2-8 h with minimal impact on the growth of representative members of the normal gut microbiota. These results suggest that the drugs and microbial metabolite scaffolds may offer alternative avenues to address unmet needs in disease prevention and treatment.
IMPORTANCE
The most frequent infection associated with hospital settings is , which can cause fatal diarrhea and severe colitis, toxic megacolon, sepsis, and leaky gut. Those who have taken antibiotics for other illnesses that affect the gut's healthy microbiota are more susceptible to infection (CDI). Recently, some reports showed higher recurrence rates and resistance to anti-, which may compromise the efficacy of CDI treatment. Our study is significant because it is anticipated to discover novel microbial metabolites and drugs with microbial origins that are safe for the intestinal flora, effective against , and reduce the risk of recurrence associated with CDI.
PubMed: 38940508
DOI: 10.1128/msphere.00273-24 -
Small (Weinheim An Der Bergstrasse,... Jun 2024Adjuvants play a critical role in the induction of effective immune responses by vaccines. Here, a self-assembling nanovaccine platform that integrates adjuvant...
Adjuvants play a critical role in the induction of effective immune responses by vaccines. Here, a self-assembling nanovaccine platform that integrates adjuvant functions into the delivery vehicle is prepared. Cationic Lentinan (CLNT) is mixed with ovalbumin (OVA) to obtain a self-assembling nanovaccine (CLNTO nanovaccine), which induces the uptake and maturation of bone marrow dendritic cells (BMDCs) via the toll-like receptors 2/4 (TLR2/4) to produce effective antigen cross-presentation. CLNTO nanovaccines target lymph nodes (LNs) and induce a robust OVA-specific immune response via TLR and tumor necrosis factor (TNF) signaling pathways, retinoic acid-inducible gene I (RIG-I) receptor, and cytokine-cytokine receptor interactions. In addition, CLNTO nanovaccines are found that promote the activation of follicular helper T (Tfh) cells and induce the differentiation of germinal center (GC) B cells into memory B cells and plasma cells, thereby enhancing the immune response. Vaccination with CLNTO nanovaccine significantly inhibits the growth of ovalbumin (OVA)-expressing B16 melanoma cell (B16-OVA) tumors, indicating its great potential for cancer immunotherapy. Therefore, this study presents a simple, safe, and effective self-assembling nanovaccine that induces helper T cell 1 (Th1) and helper T cell (Th2) immune responses, making it an effective vaccine delivery system.
PubMed: 38940386
DOI: 10.1002/smll.202402792 -
Veterinary Medicine and Science Jul 2024Toxoplasma gondii is a widely prevalent zoonotic protozoan parasite in humans and warm-blooded animals worldwide. Infection of humans by this parasite can result in...
BACKGROUND
Toxoplasma gondii is a widely prevalent zoonotic protozoan parasite in humans and warm-blooded animals worldwide. Infection of humans by this parasite can result in severe clinical symptoms, particularly in individuals with congenital toxoplasmosis or immunocompromised patients. Contamination mainly occurs through foodborne routes, especially the consumption of raw or undercooked meat from animals.
OBJECTIVES
The aim of this study was to use PCR to detect T. gondii in tissues and organs of buffaloes and cattle slaughtered at Tabriz slaughterhouse, in Iran.
METHODS
Fifty grams of heart, thigh, diaphragm and tongue from 50 buffaloes and 100 cattle slaughtered at the Tabriz industrial slaughterhouse were selected for sampling using a combination of convenience sampling. The samples were tested using a previously published PCR method.
RESULTS
Out of the 150 animal samples, T. gondii was detected in 10 (6.7%, 95%CI: 3.2-11.9), including one buffalo (2%, 95%CI: 0.1-10.6) and nine cattle (9%, 95%CI: 4.2-16.4). There was no statistically significant difference in the rate of T. gondii infection among cattle based on age and sex (p > 0.05).
CONCLUSIONS
The results indicated a potential risk of T. gondii transmission to humans through the consumption of infected meat. Therefore, appropriate and effective preventive measures should be taken to limit the transmission of this parasite to humans, and the consumption of raw and undercooked meat should be discouraged.
Topics: Animals; Buffaloes; Iran; Cattle; Toxoplasmosis, Animal; Abattoirs; Toxoplasma; Cattle Diseases; Female; Male; Prevalence; Polymerase Chain Reaction
PubMed: 38940227
DOI: 10.1002/vms3.1511 -
Bioinformatics (Oxford, England) Jun 2024World Health Organization estimates that there were over 10 million cases of tuberculosis (TB) worldwide in 2019, resulting in over 1.4 million deaths, with a worrisome...
MOTIVATION
World Health Organization estimates that there were over 10 million cases of tuberculosis (TB) worldwide in 2019, resulting in over 1.4 million deaths, with a worrisome increasing trend yearly. The disease is caused by Mycobacterium tuberculosis (MTB) through airborne transmission. Treatment of TB is estimated to be 85% successful, however, this drops to 57% if MTB exhibits multiple antimicrobial resistance (AMR), for which fewer treatment options are available.
RESULTS
We develop a robust machine-learning classifier using both linear and nonlinear models (i.e. LASSO logistic regression (LR) and random forests (RF)) to predict the phenotypic resistance of Mycobacterium tuberculosis (MTB) for a broad range of antibiotic drugs. We use data from the CRyPTIC consortium to train our classifier, which consists of whole genome sequencing and antibiotic susceptibility testing (AST) phenotypic data for 13 different antibiotics. To train our model, we assemble the sequence data into genomic contigs, identify all unique 31-mers in the set of contigs, and build a feature matrix M, where M[i, j] is equal to the number of times the ith 31-mer occurs in the jth genome. Due to the size of this feature matrix (over 350 million unique 31-mers), we build and use a sparse matrix representation. Our method, which we refer to as MTB++, leverages compact data structures and iterative methods to allow for the screening of all the 31-mers in the development of both LASSO LR and RF. MTB++ is able to achieve high discrimination (F-1 >80%) for the first-line antibiotics. Moreover, MTB++ had the highest F-1 score in all but three classes and was the most comprehensive since it had an F-1 score >75% in all but four (rare) antibiotic drugs. We use our feature selection to contextualize the 31-mers that are used for the prediction of phenotypic resistance, leading to some insights about sequence similarity to genes in MEGARes. Lastly, we give an estimate of the amount of data that is needed in order to provide accurate predictions.
AVAILABILITY
The models and source code are publicly available on Github at https://github.com/M-Serajian/MTB-Pipeline.
Topics: Mycobacterium tuberculosis; Machine Learning; Drug Resistance, Bacterial; Microbial Sensitivity Tests; Anti-Bacterial Agents; Whole Genome Sequencing; Genome, Bacterial; Humans
PubMed: 38940175
DOI: 10.1093/bioinformatics/btae243 -
Annals of Agricultural and... Jun 2024. Pets infected with zoonotic pathogens might become a source of infections for their owners, especially those who are immuno-compromised. The aim of this report is to...
. Pets infected with zoonotic pathogens might become a source of infections for their owners, especially those who are immuno-compromised. The aim of this report is to describe a case of chronic, untreatable pneumonia in a domestic ferret. The subject was a 5-year-old female ferret suffering from recurrent pneumonia. Ante-mortally, swabs from the nasal cavity, alveolus and throat were collected from the animal. Post-mortally, lesioned organ fragments were collected. Standard microbiological testing was performed. Additionally, mycobacterial diagnosis including culture and molecular tests was performed. . The co-infection of Mycobacterium avium and Klebsiella pneumoniae was microbiologically confirmed. This case demonstrates the need to pay attention to the possibility of zoonotic pathogens in ferrets. Veterinarians diagnosing ferrets are potentially exposed to Mycobacteria spp. infections and other pathogens.
Topics: Animals; Ferrets; Female; Klebsiella pneumoniae; Coinfection; Klebsiella Infections; Mycobacterium avium; Tuberculosis; Fatal Outcome
PubMed: 38940116
DOI: 10.26444/aaem/174216 -
Annals of Agricultural and... Jun 2024Correlations between the number of milk somatic cells (SCC), the number of microorganisms, and the content of basic components of milk were studied on five farms (F1-F5)...
INTRODUCTION AND OBJECTIVE
Correlations between the number of milk somatic cells (SCC), the number of microorganisms, and the content of basic components of milk were studied on five farms (F1-F5) with cows of the same breed, but with different milking systems.
MATERIAL AND METHODS
From each farm, 50 Holstein Friesien milk samples were collected once a month (250 samples/month; n=3,000) during March 2022 - February 2023. Samples from farms F1 and F5 were tested for fat, protein, lactose, no fat dry matter content (FTIR spectroscopy), for the SCC (Fossomatic 7), and for the differential cells (Vetscan DC-Q).
RESULTS
The highest fat content was confirmed on farm F5 (3.85 ± 1.70%) and F4 (3.82 ± 0.21%) with automatic milking system (AMS). However, from the point of view of protein content, these farms showed slightly lower values (<0.05). F1 did not meet the minimum required amount for fat content (2.84 ± 0.81%) set by the legislation of the Slovakia. The comparison shows that there is not much difference in cell size between healthy cells and mastitis cells. The average size of healthy cells was approximately 8.77 ± 0.49 μm. In the monitored period, the average values determined were at the level of 292,000/mL (5.46 ± 0.72 log10 SCC) in cow milk samples, while for the rest of the year, the values remained at 256,000/mL (5.40 ± 0.80 log10 SCC). F1 was categorized as a positive farm with a high TLC (total milk leucocyte count) concentration (5.58 log10 cells/mL, 406.65 ± 53.80 × 10 cells/mL) and a predominant NEU fraction (61%). Farms F2, F4, and F5 were classified as negative farms (TLC was 4.70 ± 0.26 log10 cells/ml).
CONCLUSIONS
According to the results, the size of SCCs in healthy milk does not differ from SCCs found in mastitis milk. From the results, it can be concluded that the transition to the latest generation of robotic milking method can positively affect milk production and its quality.
Topics: Animals; Milk; Dairying; Female; Cell Count; Cattle; Lactose; Slovakia; Milk Proteins; Lactation
PubMed: 38940103
DOI: 10.26444/aaem/187170